Rapid cycle radial draw forming machine



Dec. 18,1962

R. F. DE MARCO ET AL RAPID CYCLE RADIAL DRAW FORMING MACHINE Filed April7, 1960 5 Sheets-Sheet 1 INVENTOR5. P05527- D'MAEc'O plus J. NAsvYr/.sBY

l 4:* AHORA/Ey Dec. 18, 1962 R. F. DE MARCO ETAL 3,068,928

RAPID CYCLE RADIAL DRAW FORMING MACHINE Filed April 7, 1960 Dec. 18,1962 R. F. DE MARCO ETAL 3,068,928

RAPID CYCLE RADIAL DRAW FORMING MACHINE 5 Sheets-Sheet .'5

Filed April '7, 1960 INVENTORJ'.

P05527 E 75 MARCO v if A Trae/VEK Dec. 1s, 1962 R. F. DE MAR@ mL3,068,928

RAPID CYCLE RADIAL DRAW FORMING MACHINE INVENTORS.

,9055er DE MARC@ P/us J. NAsvYr/s u2 A rme/vfx Dec. 18, 1962 R. F. DEMARCO EIT AL RAPID CYCLE RADIAL DRAW FORMING MACHINE Filed April 7, 19605 Sheets-Sheet 5 1NVENTOR5. 055?? E @5M/1ero P/as J. /vAsVyT/s BY g Jaw

A TTOENEK United States Patent Oiitice 3,068,928 Patented Dec. 18, 19623,068,928 RAPID CYCLE RADIAL DRAW FORMING MACHINE Robert F. De Marco,Mentor, and Pius J. Nasvytis, Cleveland, Ohio, assignors to The CyrilBath Company, Solon, Ohio, a corporation of Ohio Filed Apr. 7, 1960,Ser. No. 20,689 7 Claims. (Cl. 153-32) This invention relates to astretch forming machine and particularly to a stretch forming machinefor forming elongated metal stock about a side face die of which theface has a rise and tall in an endwise direction.

The present machine is an improvement on the machine i ,disclosed in acopending application of Robert F. De

their relative senses for convenience in describing relative positionsof parts, and not as absolutes.

A general object of the present invention is to provide a rapid cyclestretch forming machine of simple Vconstruction in which the heavy andexpensive .power applying mechanisms heretofore required have beenreduced to -a minimum.

A principal object is to provide a stretch forming machine employing astretch head carried on a swinging arm which is adapted to swing aboutan upright axis so as to swing the stock about upright axes toward theside face of the die and concurrently to swing the stock about ahorizontal axis so that head rises and falls and thereby "lifts andlowers the stock to conform it to ,the rise and fall of theside face ofthe die endwise of u the die face.

Various other objects and advantages of the inven- I tion will becomeapparent lfrom the following description -wherein reference is made tothe drawings in which:

FIG. 1 is a front elevation of themachine embodying the principles ofthe present invention;

FIG. 2 is a top plan View of the machine illustrated in FIG. .1, thestretch forming mechanism on the left hand arm being omitted forclearness in illustration;

FIGS. 3, 4, and 5 are enlarged fragmentary cross sectional views takenon the lines 3 3, 4-4, and 5"-5,

'.respectively, of FIG. l;

FIGS. 6 and 7 are a side elevation and a right end elevation,respectively, of the stretch forming gripping head and mandrel mechanismfor the left hand arm of FIG. l;

FIGS. 8 and 9 are a side elevation and a left end ,elevation of thestretch forming gripping head and `mandrel mechanisms of the right handarm in FIG. l;

and

FIG. l is a pneumatic flow control diagram for the present machine.

Referring to the drawings, the preferred embodiment of the machineincludes a horizontal frame 1 on which `is mounted a platform or table 2which supports a side face die 3 with the side face generally upright.Mounted on the frame 1 is an upright sleeve 4 in which an upright pivotpost 5 is mounted for rotation about Vits axis. `Carried on the pivotpost 5 are transverse or horizontal lcoaxial pivots 6 which support a'rocking connector 7 for terms horizontal, vertical and the like are usedin rocking about their common axis and for rotation with the uprightpivot post 5.

An arm 8 is iixedly secured to the connector 7 and extends generallyhorizontally outwardly from the axis of the pivot post 5 and in adirection generally endwise of the side face of the die 3. Fixedlyconnected to the arm 8 is a driving arm or bracket 9 which extend-sgenerally radially from the axis of the pivot post 5 and which, at itsouter end, is provided with a suitable yoke 10.

Carried on the frame 1 is a suitable anchor bracket 11 to which areversible pneumatic piston and cylinder as'- semblage 12 is pivotallyconnected for swinging. about an axis parallel to the axis of the post5. 'Ihis assemblage includes a cylinder 13 in which a piston 14 having arod 15 is reciprocable. The rod 15 is pivotally connected by an uprightpivot 16 to the yoke 10 so that upon ex :tension of the assemblage 1'2,the arm 8 is swung to its forward or starting position and uponretraction of the assemblage 12 the arm is swung from its forwardposition toward a rearward position for laying the stock along the sideface .of the die.

As mentioned in the objects, the machine is particularly adapted forstretch forming stock along the die side face' which undulates or has arise and fall endwise at some preselected portion between its ends. Inorder to cause the stock being stretch formed to follow the rise andfall of the side face of the die, the arm 8 is provided with a suitableroller 20 which` rides on a track 21 carried on the frame 1 andwhichis'held down by a `suitable overhanging guide track 22. By virtueof the rise and fall of the track 21 and guide track 22, the arm V8 ismade to rise and fall by rocking about theI common axis of the pivots 6as it is swung from its forward to its rearward position and returned bymeans of the assemblage 12.

In order to apply stretch forming tension to` the stock endwise of thestock, the arm is provided with a suitable gripping and mandrelinserting mechanism which is movable endwise of the arm 8.

For supporting the mechanism, later to be described, for movementendwise of the arm 8, acarriage 23 is mounted on the arm 8 on suitableslideways 24 forV sliding movement endwise of the arm 8. Thecarriage ismoved along its slideways by a 'suitable tension cam track 25 which ismounted on the frameV 1. The cam track 25 is engaged by a suitable camroller 26 mounted on the under side of the carriage" 23. A compressionspring 27 is interposed between a bracket 28 on the carriage and abracket 29 on the arm and yieldably urges the carriage in a direction soas to hold the cam roller 26 in firm rolling engagement with theoperating face of the cam track 25. Thus, upon swinging of the arm 8about the axis of the post 5, the cam track -25 causes the carriage to'move the gripping and mandrel inserting mechanism endwise away from thetable 2 and to permit the mechanism to return under restraint toward thetable 2 the distances which provide the required tension on the stockbeing formed.

The gripping and mandrel operating mechanism, mounted on the carriage23, is arranged for gripping one end of the stock after inserting amandrel into the stock for internally supporting the gripped end. Themandrel is to prevent collapse of the stock by the gripping pressure'and for support of the stock internally for a distance beyond theportion gripped to prevent buckling during stretch forming.

As best illustrated in FIGS. 1, 6 and 7, this mechanism, indicatedgenerally at 30, is mounted on the carriage 23 for swinging about anupright axis. For this purpose, the carriage 23 is provided with anupright bracket 31 having yoke arms 32 which receive and are pivotally34 in alignment with the mandrel.

connected to a suitable tongue 33 fixedly secured on a swinging stretchhead and mandrel support 34. The support 34 is provided with a skid pad35 which engages an upwardly facing complementary skid pad 36 on thecarriage 23. Thus, the swinging support 34 may swing about an uprightaxis for maintaining proper alignment with the axis of the stock beingformed.

Mounted on the swinging support 34 is a stock gripping stretch head,indicated generally as 37. The head comprises vessentially a stationaryjaw 40 adapted to lit the cross sectional contour of the stock S to bestretch formed and a movable jaw 41 which is adapted to be movedrelative to the jaw 40 so that the jaws cooperate in rmly clamping thestock with the mandrel inserted therein, `whereby the stretch formingtension can be applied to die stock.

In order to support the jaw 41 for movement toward and away from the jaw40 and for moving the jaw by a suitable power means, the jaw 40 ismounted in between suitable yoke arms y42 which are pivotally connectedby a horizontal pivot 43 to the swinging support 34. The jaw 41 isprovided with suitable lineal guides 44 which operate in guideways 45extending endwise of the yoke arms 42 for guiding the jaw for propercooperation with the jaw v40. To 'move the jaw 41 toward and away fromthe jaw 40, the jaw 41 is connected by a toggle pin 47 to a link 48which, in turn, is connected to a toggle pin 49'. The toggle pin y49 isconnected to a cooperating toggle link 50 `which is pivotally connected,as indicated at 51, to the arms 42. The pin 49 is connected to the rod52 of a piston 53 which is operable in acylinder 54 of a reversiblepneumatic piston'and cylinder assemblage, indicated generally Yat 55.The assemblage 55 is connected by a pivot '56 to the support 34 so thatit can rock about a horizontal axis and thus accommodate itself forproper angularity with respect to the 'toggleliriks 48 and 50 whichoperate the jaw 41.

The gripping head and mandrel inserting mechanism also includes amandrel guide 60 which is arranged at the outboard end of the jaws 40and 41 in alignment therewith. The guide `60 is mounted in xed positionon the support 34. A mandrel 61 having a rigid non-compressible head 62is mounted for sliding movement in the guide 60 so as .to move to anextended position between the jaws and to a retracted position to theoutboard end of the jaws. A suitable reversible or spring returnpneumatic piston and cylinder assemblage 63, including a cylinder 64 anda piston 65, having a rod 66 connected to thehead 62 of the mandrel iscarried on the support Thus the mandrel can be retracted by theassemblage `63 from between the vjaws 40 and 41 endwise of the stock Swhile the stock is being inserted and, after insertion of the stockbetween .the jaws, can be inserted into the stock endwise preparatory toclosingr the jaws. The head 62 of `the mandrel is, as mentioned, veryrigid so that when the jaws are operated by the toggle to apply clampingpressure to the stock, the head reinforces the stock internally andprevents crushing or distortion of the stock.

The mandrel 61 may be relatively short or long, depending upon thedistance to which it is to be inserted in the stock beyond the inboardend of the jaws. This, in turn, depends on the distance the bends in thestock are to be from the end. 1In the form illustrated, a relativelyshort mandrel is all that is required.

With the structure thus far described, it is apparent that the stock canbe held in fixed position relative to the die 3 at a location which isin spaced relation to its left end. The stock can be stretch formed,without being distorted in cross section, both in a direction forwardlyand rearwardly of the machine and vertically thereof by inserting themandrel, gripping the stock, with the mandrel head therein, in the jaws40 and 41, and swinging the arm 8 from the forward position to arearward position while the arm 8 is moved up and down as well asforwardly and rearwardly.

Quite generally, however, it is desirable to form the stock along theside face of a die which recedes from some preselected locationintermediate its ends, usually from its mid-portion to the rear of thedie and also from a higher position at said location to a lower positiontowards the ends. Generally, the piece to be formed is symmetrical andthe peak of the side face is at the longitudinal mid-portion of the dieface. In such instances, generally, the axis of the pivot post 5 isarranged at this location which is indicated by the letter X in FIG. l,and the die slopes downwardly from the portion X in both directionstowards the ends and also slopes rearwardly of the apparatus from theportion X.

ln order to form stock about a die of this nature, an additional orsecond arm is provided. Referring to FIGS. l, 2 and 4, a suitablesupporting member 70 is mounted `on the frame 1. Extending upwardlythrough the surface of the member 70 is an upright pivot 71 by which arotatable support 72 is pivotally connected to the supporting `member70` for rotating about the upright axis. Mounted on the rotatablesupport 72 for rocking about a horizontal axis is an arm 73, the armbeing'pivotally secured to the support 72 by a suitable horizontal pivot74. Mounted von the arm 73 is a stock gripping head, indicated generallyat 75, and a mandrel supporting and operating mechanism, indicatedgenerally at 76. The stock gripping mechanism is best illustrated inFIGS. A8 and 9. This `mechanism is substantially the same as themechanism 30 on the arm 8. It comprises a stationary gripping jaw `77and a movable gripping jaw 78, the jaw 77 being tixedly mounted on asupportingjplate 79' which is tixedly positioned on the arm 73. The jaw78 has'suitable guides 80 which voperate in the guideway 81 in a pair ofyoke arms 82. The yoke arms are pivotally connected by a 'pivot 82a tothe plate 79. Connected to the movable jaw 78 by a toggle pin 83 is alink 84 which, in turn, is connected by a toggle pin to a link 86. Thelink 86 is connected to a piston rod 88 of a piston 89 operable in acylinder 90 of a reversible pneumatic piston and cylinder assemblage 91.This piston and cylinder assemblage 91 is connected by a horizontalpivot 92 to the plate 79 so as to align itself properly during expansionand retraction of the toggle.

Mounted on the plate 79 is a hollow support and guide 93 which receivesand guides a mandrel 94 endwise between the jaws 77 and 78 into thestock. A mandrel 94 is provided with a rigid head 95 near the outboardend of the jaws 77 and 78. The mandrel is slidable endwise through thehollow support and guide 93. The guide 93 is provided along one edgewith a slot 96 through which extends a pedestal 97 which supports thehead 95 within the guide 93. The pedestal 97 is mounted on a slidingcarriage 98 which is connected to a piston rod 99 of a reversiblepneumatic piston and cylinder assemblage 100, including a piston 101.Upon extension of the piston rod 99, the mandrel I94 is moved to aretracted position and upon retraction of the piston rod 99, the mandrel94 is moved through the end of the stock to an extended position todispose the head 95 beyond the locations to be curved. Generally, themandrel 94 is the longer mandrel and extends to or very slightly beyondthe I.bend at the mid-portion of the die face for supporting the stockinternally at the Ibend at its mid-portion. The head is non-compressibleand fits accurately the interior of the stock and prevents distortionand collapse of the stock by the jaws, and assures firm clampingpressure.

Since the support 72 is rockable about horizontal and vertical axes, itcan be aligned so that, in the starting position, the line of pullbetween the jaws 40 and 41, on the one hand, and the jaws 77 and 78, onthe other, is lineal and slopes downwardly alongside the die face towardthe jaws 77 and 78 at that portion of the die face from the line X inFIG. 1 toward the end of the die face adjacent the jaws 77 and 78. Thus,as illustrated in FIG. 1, the stock is aligned vertically throughout thedistance from its right hand end and to the preselected position ormid-portion at line X with the side face of the die it is to engage, butfrom the portion at line X toward its left hand end the stock continueson a rising straight line entirelyV to its left end, then rising abovethe level of the left .portion of the side face which it is to engage.The stock is also close to the right end of the side face. As a ,resultof this action, very little swinging and rocking movement of the arm 73is required in the forming operation. However, this length of stock isto be clamped by the jaws at its opposite ends preparatory to beingengaged with the side face of the die. Yet the side face of the dieslopes rearwardly as well as downwardly from the preselected ormid-portion X toward the ends. Accordingly, the straight length of stockextending from one set of jaws to the other set makes a predeterminedangleA with the rightA hand portion of the forward face of the dieadjacent the right hand gripping jaws 77 and 7S and a greater angle Brelative to the left hand portion of the `forward face. The jaws 77 and78 preferably are arranged close to the axis of the pivot 71 so that thestock is gripped just beyond the right hand end of the die face, yetclearing the die face. It can be swung clockwise in FIG. l. When thestock is swung clockwise by the swinging of the arm 8 to the rear, thestock will rst be brought into contact with the right hand end of theface of the die and laid on the face progressively therefrom to themid-portion at line X and then, thereafter, progressively from the lineX to the left end of the die. However, this angle at A at the startingposition would cause an abrupt Ibend to the stock adjacent the jaws 77and 78 except for the fact thatthe jaws are near the axis of the pivot71 and the support 72 can swing about that axis.

When the stock is swung into engagement with the right hand portion ofthe die face, the jaws 77 and 78 and the mandrel 94 swing so that thestock and mandrel become substantially tangential to that end of the dieface.

However, even the weight of the arm 73 and its supported mechanism wouldtend to impart a severe binding stress to the stock at this point.Accordingly, means are provided to assure that the arm 73 swings at adifferent rate than the arm 8, though swinging in the same clockwisedirection, and furthermore swings through a lesser angle than the arm 8during the entire forming operation. 'For example, the arm 8 will swingabout the axis of its pivot post 5 through the angle B from starting tofinal position, whereas the arm 73 need swing only through the muchlesser angle A.

In order to control this operation so that the arm 8 swings both fasterand farther than the arm 73, a suitable tie member 105 is pivotallyconnected at 106 to the bracket 9 and thereby to the arm 8 so that theend of the tie member 10S moves with the arm 8 during the swingingmovement thereof on the forming and return strokes. The member 105 isconnected, as indicated at 107, to a suitable bracket 108 which is rigidwith the arm 73. Accordingly, upon swinging of the arm 8 about the axisof the pivot post 5, the arm 73 is swung about the axis of its pivot 71.However, the point of connection at 107 is farther from the axis of thepivot post 71 than the -point of connection 106 is from the axis of thepivot 5. Therefore, depending on the degree of difference in the lengthof these radii, the arm 73 moves through a less angle than the arm 8.The arm 73, therefore, yis constrained to swing at a different speed atall times than the arm 8 and also to swing in the same directionangularly about its axis as the arm 8.

Mounted on the frame 1 is a suitable adjustable stop 110 -which ispositioned to be engaged by the support 72 and which stops the swingingof the arm 73 in a position 6 in which itholds the stock tangent to theIside face at the right end of the die face 3. A suitable lost motionconnection is provided in the tie member and a heavy spring 112 isinterposed so that, when the stops and support engage, any additionalslight movement of the arm 8 and its bracket 9 can be relieved.

In order to operate the various mechanisms, a suitable source ofpositive pressure air is provided and is connected to suitable reversingand cut-olf valves of the respective piston and cylinder assemblages.Since all of these valves'are the same in type and operation, only .onewill be described in detail.

The valve 121 is connected by the pressure line 122 to the `source 120and is connected to the atmosphere at 123. This valve is connected toopposite ends of the cylinder 63 and, in intermediate position, connectsthe ends of the cylinder together for servicing and repairs. At one ofthe operating positions, indicated at 124, it connects the assemblage soas to cause retraction of the piston rod 66 and at the other operatingposition, indicated at 125, it causes the extension of the piston rod66. Valves 126, 1.27, 128 and 129, all of the same type, arecorrespondingly connected to the assemblages `55, 12, 91 and 100,

respectively. Each ofthe valves is operable independently of the others,and preferably each is operable by suitable solenoids, such as indicatedat 130 on the valve 121, so that the valves can be operated from acommon control panel.

It is apparent from the foregoing description that the machine isrelatively simple in structure and effective for rapid cycle bending ofstock which must be curved concurrently both in a horizontal plane andin a vertical plane Ibecause of the rise and fall of the die faceendwise. Furthermore, the stock can be formed without imposing anysevere bends adjacent the ends of the die inasmuch as the arms are tiedtogether for movement at different speeds in the same direction. Thedegree of stretch can be accurately controlled by the cam track. Thesefeatures render the machine particularly suitable for forming largenumbers of identical parts.

Having thus described our invention, we claim:

l. In a stretch forming machine, a frame, a horizontal support thereon,a side face die in fixed position on the support, a lpair of arms,supporting means mounting the arms on the frame for swinging aboutupright axes, respectively, power operated stretch forming meansincluding gripping heads on the arms, respectively, adapted forconnection to opposite ends of a length of stock for applying endwisetension to the stock, power operated means connected to the arms andoperative to swing the arms about their respective axes whileconstraining one arm to swing at a different angular velocity than theother arm.

2. The structure according to claim 1 wherein said power operated meansconstrains one of the arms to swing at a different speed from the otherarm while the arms are swinging in the same direction.

3. The structure according to claim 1 wherein said power operated meansincludes a tie member operatively connected at its ends to the arms,respectively, the connection with one arm being a greater distance fromthe upright axis of said one arm than the 'distance at which theconnection of the member with said other arm is from the axis of saidother arm.

4. |In a stretch forming machine, a frame, a horizontal support thereon,a side face `die in fixed position on the support, a pair of arms,supporting means mounting the arms on the frame for swinging aboutupright axes, respectively, power operated stretch forming meansincluding gripping heads on the arms, respectively, adapted forconnection to opposite ends of a length of stock for applying endwisetension to the stock, said side face die sloping endwise downwardly ineach direction from a predetermined location thereon toward its ends,additional means on one arm maintaining the arm in positions in whichits associated gripping head is in a lower position than the grippinghead of the other arm with the line of pull between the heads alignedwith the side face of the die from the predetermined location on the dieface to said lower head, and additional supporting means supporting theother arm for up and down movement for lifting and lowering its grippinghead during swinging of the other arm, and control means for controllingsaid up and down `movement so as to lay the stock on the die facebetween said predetermined location and said other head after it hasbeen laid on the die face between said predetermined location and saidone head.

5. `In astretch forming machine, a frame, a horizontal support thereon,a side face die in xed position on the support, a pair of arms,supporting means mounting the arms on the frame for swinging aboutupright axes, re-

spectively, power operated stretch forming means including grippingheads on the arms, respectively, adapted for connection to opposite endsof a length of stock for applying endwise tension to the stock, saidarms being positionable in a starting position such that the line ofpull between the heads is lineal and spaced from the side face, saidside face has a horizontal component of slope away from said line inboth directions from a predetermined location on the die face toward theends of the face, and means interconnecting the arms so that they swingconcurrently in the same direction of rotation about their respectiveaxes, one arm through a lesser angle than the other and thereby rst laythe stock on the die face lprogressively from one end adjacent said onearm to said predetermined location and thereafter progressively fromsaid predetermined location to said other end of the face, adjacent theother arm.

6. The structure according to claim 5 and further including stop meansfor arresting continued swinging of said one arm in the same directionafter the stock has been ylaid on the -die face from said one face endto said predetermined location.

7. The structure according to claim 5 wherein the means interconnectingthe arms include a resilient lost motion device.

References Cited in the file of 'this patent UNITED STATES PATENTS2,713,376 Bath July 19, 1955 2,830,644 Walker et al. a Apr. 15, 19582,880,780 IMackey Apr. 7, 1959 2,881,821 -Maize et al. Apr. 14, 19592,887,143 Ahonen May 19, 1959 ...LNH

